OIL BARRIER

Abstract: The invention relates to a boom which includes an elongated air-inflatable buoyant body (1) made from a fabric material, a curtain (2) which depends from the lower edge of the buoyant body, and an automatic air-filling and air-emptying valve (7) provided on the upper side of the buoyant body (1). The air valve (7) is connected directly to a connecting tube (8) which extends from the valve and through the buoyant body (1) to an open end located adjacent the lower edge of the buoyant body and intended for closure by water that penetrates the boom.

Description: OIL BARRIER The present invention relates to an oil boom intended for use in coastal waters or like waters and comprising an elongated air-inflatable buoyant body constructed from a fabric material and having a downwardly depending curtain connected to its bottom edge. The oil boom is of the self-expanding type, so as to enable it to be easily rolled-up and so as to take-up only a small amount of space when stored or transported. An automatic air-filling and air-emptying valve is provided on the upper side of the buoyant body of the boom. Oil booms of this kind are known to the art, for instance from our earlier Patent Application SE 9302257-2 and include an air-inflatable buoyant body from which a curtain depends when the boom is in use. The problem with earlier known booms of this kind is that they are liable to be punctured, so that water is able to enter the buoyant body and therewith lower its buoyancy to an extent such as to cause the upper part of the boom to sink beneath the surface of the water, and also that when taking-up the boom, it is difficult to drain therefrom any water that may have entered the buoyant body whilst the boom was in use. Another problem resides in the construction of the framework which functions to hold the boom stretched in its state of use and which shall be capable of being collapsed when wishing to pack-up the boom. An object of the present invention is therefore to provide a boom with which it is guaranteed that the boom will never sink in the water to a depth at which its oil-delimiting capacity is jeopardized, even should the buoyant body be punctured. A further object of the invention is to provide a boom which can be manufactured easily and which has a framework that can be easily fitted and that is also reliable in operation. Still another object of the invention is to provide a boom from which water that has entered the boom can be easily drained therefrom when taking-up the boom. These objects are achieved with an inventive boom having the characteristic features set forth in the following Claims. The invention will now be described in more detail with reference to exemplifying embodiments thereof and also with reference to the accompanying drawings, in which Fig. 1 is a perspective sectional view of an inventive boom construction; and Fig. 2 is a side view of a framework for outwardly stretching of the boom shown in Fig. 1. The inventive oil boom thus includes an air-inflatable buoyant body 1 and a curtain 2 which will depend from the bottom edge of said body when the boom is in use. The bottom of the curtain is provided with ballast accommodating pocket means 3, into which there can be inserted a curtain ballast chain, for instance. The buoyant body 1 and the curtain 2 are both produced from an airtight and watertight fabric, preferably a fabric which can be heat-welded or even more preferably high-freguency welded. The buoyant body 1 is divided longitudinally into a plurality of sections by impervious bulkheads 4, which are formed by fastening fabric within the buoyant body against the inside of the body walls, this fabric material preferably being the same material as that from which the buoyant body is made. Mounted adjacent the impervious bulkheads 4 are expandable frames 5 which function to extend or stretch the buoyant body, as described in more detail with reference to Fig. 2. Provided adjacent the lower edge of the buoyant body 1 is a drainage pocket 6, which is conveniently made from the same material as the buoyant body in general and which extends downwards along the depending curtain 2 within each segment of the buoyant body. The drainage pocket 6 is open both upwardly and inwardly towards the buoyant body 1 and also downwardly towards that part which is located in the water when the boom is laid-out. The drainage pocket 6, however, is closed almost completely by the pressure of the water acting thereon when the boom is laid-out. Mounted on the top of each segment of the buoyant body is a valve 7 of known type which guarantees the introduction of air into the buoyant body when expanding the same. There is connected to each valve 7 within the buoyant body a respective airtight connecting pipe 8, which is conveniently made of the same material as the buoyant body and which extends trans¬ versely through the buoyant body in its vertical direction and discharges immediately beneath the intended waterline, in the upper part of the drainage pocket 6. Fig. 2 thus illustrates a framework 2 which stretches or extends the buoyant body outwardly and which has the same geometrical shape as the buoyant body in its outwardly stretched state. The framework includes four arms which are connected by means of joints, namely an upper joint 9, a lower joint 10 and two side joints 11. The arms are comprised of two upper arms 12 and two lower arms 11, wherein the lower arms are slightly shorter than the upper arms. The upper joint 9 and the lower joint 10 are mutually connected by means of a pull spring 14 which endeavours to pull the framework 5 to the state shown in Fig. 2, which is the maximum outwardly stretched state of the framework. The two side joints 11 may be constructed to form a maximum limit to which the framework can be extended or stretched, for instance as a result of the mutual abutment of shoulders 15. Further shoulders 16 are provided adjacent the upper and the lower joints 9, 10 and abut one another when collapsing the framework so that the boom can be rolled-up. The upper and the lower arms 12, 13 are attached to their respective upper and lower joints 9, 10 at a given angle in relation to the abutment surfaces of the shoulders 16, therewith preventing the arms 12 and 13 adjacent respective joints 9 from lying completely parallel with or against one another. To achieve this, the arms 12 and 13 are conveniently made of a resilient material, for instance acryl of the same type as that from which sail slats are made, so that the arms 12 and 13 will be flexible. When a framework 5 constructed in the aforesaid manner is compressed by an external force acting on the joints 11, the joints can be pressed completely against one another and the joints 9 and 10 will therewith also be pressed together so as to bring the shoulders adjacent respective joints into mutual abutment and causing the resilient arms 12 and 13 to bend • inwards towards the joints ll. This will also result in a given biassing force which strives to bend the framework 5 outwardly to the position shown in Fig. 2 when the external force acting on the joints 11 is removed, i.e. when the boom is to be laid-out. The function of the inventive boom is such that when a rolled- up boom is released in the water, the framework will extend the buoyant body 1 and the respective valves 7 will allow air to enter through the connecting tubes 8. Since the connecting tubes 8 terminate in the upper edge of the drainage pocket 6, the air will flow upwards into the buoyant body itself. As the boom is laid-out, the pressure of the water will close the drainage pocket 6 at the lower edge of the boom, which therewith forms a closure means which will ensure that the air will definitely rise upwards into the buoyant body 1. The water level will lie immediately above the bottom edge of the drainage pocket and any water that enters through the drainage pocket 6 will also contribute in closing the connecting tubes 8 and therewith close respective valves 7. Should any of the sections of the buoyant body 1 be punctured, the remaining sections will still provide sufficient buoyancy to prevent the buoyant body from sinking to any appreciable extent in relation to the position adopted by the boom when all sections of the buoyant body are watertight and support the boom . The boom can be easily rolled-up when lifted out of the water, and any water that has penetrated into the buoyant body can be easily evacuated through the now downwardly open drainage pocket 6, together with the air.

Claims: CLAIMS 1. A boom comprising an elongated air-inflatable buoyant body (1) made from a fabric material, a curtain (2) which in use depends from the lower edge of the buoyant body, and automati¬ cally operating air-filling and air-emptying valves (7) mounted on the upper side of the buoyant body (1), character¬ ized in that each air valve (7) is connected directly to an associated connecting tube (8) which extends from the valve through the buoyant body (1) to an open end which is located adjacent the bottom edge of the buoyant body (1) and which is intended to be closed by water that penetrates into the boom. 2. A boom according to Claim 1, characterized by a downwardly open drainage pocket (6) which is connected to the lower edge of the buoyant body (1) and open towards the interior of said body, wherein the connecting tube (8) opens into the drainage pocket (6) . 3. A boom according to Claim 1 or 2, characterized in that the boom is divided longitudinally into a plurality of sections by impervious bulkhead means (4) ; and in that at least one air valve (7) and associated connecting tube (8) are provided within each such section. 4. A boom according to Claim 2 and 3, characterized in that at least one drainage pocket (6) is provided for each boom section. 5. A boom according to any one of the preceding Claims and including a plurality of frameworks (5) mounted in the buoyant body (1) and functioning to stretch said body outwardly, said framework including four arms (12, 13) which are connected by means of joints (9, 10, 11), of which two opposing joints (9, 10) are mutually connected by means of an intermediate pull spring (14), characterized in that the two joints (9, 10) which are mutually connected by means of said pull spring (14) are constructed so as to prevent said joints from being pressed together when a compressing force is applied external¬ ly on the two other joints (11) of the framework; and in that the arms (12, 13) are made from a resilient or flexible material. 6. A boom according to Claim 5, characterized in that the resilient or flexible arms (12, 13) are attached to the joints (9, 10) that are mutually connected by means of said pull spring (14) such that when the framework is in its compressed or collapsed state, said arms will form an angle ( ) to the plane that passes through the two joints (9, 10) connected by said pull spring (14). 7. A boom according to Claim 5 or 6, characterized in that the resilient or flexible arms (12, 13) are made of fiberglass reinforced acryl.

Inventors: HJALMARSSON STEFAN, HJALMARSSON, STEFAN
Applicants: BOHUS INVEST AB, HJALMARSSON STEFAN, HJALMARSSON, STEFAN
Application year: 1994
Main classification: E02B15
IPC codes: E02B15